Prokaryotic cells

• Prokaryotic cells

  
• How are they different to eukaryotic cells?

  ~ The cells are much smaller

  ~ No membrane-bound organelles

  ~ Smaller ribosomes

  ~ No nucleus

  ~ Have a cell wall made of murein

  ~ They may also contain: plasmids, a capsule around the cell and flagella.
• What do mesosomes do?

  They're inward folds of the cell membrane that provide a large SA for the attachment of the enzymes involved in respiration.
• What type of ribosomes are found in prokaryotic cells?

  70s ribosomes (also found in mitochondria and chloroplasts)
• They have no nucleus...


  Instead there is a singular and circular loop of DNA that is free in the cytoplasm, called a nucleoid. It is not protein bound.
• The cell wall contains_______.


  murein, a glycoprotein
• What are plasmids?

  Small loops of DNA which only carry a few genes.

  
• What does a capsule do?

  A slimy layer made of protein which prevents the bacteria from desiccating (drying out) and protects the bacteria from the host immune system. It's not always present.
• What are flagella?

  Thread-like structures that rotate to enable the bacteria to move, may be one or more attached to a cell.
• Binary fission process:

  Prokaryotic organisms replicate by binary fission. They achieve this by the:

  ~ replication of the circular DNA and plasmids

  ~ division of the cytoplasm to produce two daughter cells, each with a single copy of the circular DNA and a variable number of copies of plasmids